any of the more or less continuous military expeditions in the 11th to 13th centuries when Christian powers of Europe tried to recapture the Holy Land from the Muslims
go on a crusade; fight a holy war
exert oneself continuously, vigorously, or obtrusively to gain an end or engage in a crusade for a certain cause or person; be an advocate for; "The liberal party pushed for reforms"; "She is crusading for women's rights"; "The Dean is pushing for his favorite candidate"
deprive of by deceit; "He swindled me out of my inheritance"; "She defrauded the customers who trusted her"; "the cashier gypped me when he gave me too little change"
make a victim of; "I was victimized by this con-man"
maintain or assert; "He contended that Communism had no future"
be engaged in a fight; carry on a fight; "the tribesmen fought each other"; "Siblings are always fighting"; "Militant groups are contending for control of the country"